"Movement speed, reaction time, shot power… everything is way beyond our data!" Yanagi Renji opened his eyes for once, his gaze locked firmly on Yūma across the net.
"This is just like… wait! Could it be the two of them…?" Inui Sadaharu suddenly spoke in a shocked tone, as if something had just clicked.
Yanagi instantly understood what Inui was thinking. His face also changed, staring at Yūho with disbelief. Just then, Yūho finally snapped back to awareness—but a cold smirk appeared on his face.
"Looks like you figured it out. As expected of Data Tennis players. That's right—this is a whole new level we reached through Synchronization: Fusion," Yūho said calmly.
"Fusion?! What does that even mean?" Chitose asked, confused.
"It's basically an alternate form of Ability Resonance. Since the Mutsu brothers' abilities are practically identical, they can't use normal Resonance. But instead, they took another route—by using the special power of Synchronization to merge their identical selves into a single, stronger being," Akashi explained directly.
"They can even do that?" Tachibana Kippei muttered in disbelief.
"Twins are mysterious to begin with. Combine that with deep development of Synchronization, and this isn't that surprising," Akashi continued.
"So you're saying… they've poured both of their power into one person?" Fuji Shūsuke said thoughtfully.
"No. A single person's physical capacity has limits. Their Fusion doesn't double physical stats or the five attributes. What it does is combine their explosive power, field of vision, and reaction speed—pushing their strength past the limit. But I doubt they can hold this state for long," Akashi said, his Emperor Eye having already seen through the essence of the move.
"But why is Yanagi-san's so-called data pressure not working anymore?" Kirihara raised a new question.
"Simple. Because their minds are fused, Yūho chose to take on all the data pressure by himself. That way, his brother Yūma isn't affected," Akashi explained to him.
Only now did everyone start to understand how the Mutsu brothers' Fusion worked. It made them realize just how out-of-reach the abilities of U-17 first-string players really were.
"Game! Japan team! 4-2!"
While Akashi was explaining Fusion to the middle schoolers, the Mutsu brothers had already taken the sixth game. In contrast, Inui and Yanagi now looked visibly troubled.
They were probably a little weaker than the Mutsu brothers individually to begin with, and now that the twins had Fused—even if they could still predict movements using data—their bodies couldn't keep up anymore.
"Game! Japan team! 4-3!"
Yūma's serve in the seventh game was just like Yūho's—completely beyond Yanagi's ability to handle. It felt like facing one of Ochi Tsukimitsu's Mach serves, though Ochi's were still much faster.
"Renji!" Inui suddenly called out.
"Ah, got it!" Yanagi responded instantly, as if he knew what Inui was about to do.
It was Inui's serve next. His Waterfall Serve was fast, but now that Yūho was in Fusion mode, he blocked it with even less effort than before. Yanagi and Inui were being pushed hard under the Mutsu brothers' relentless offense.
"Game! Japan team! 4-4!"
The Mutsu brothers quickly evened the score. But Mitsuya Akuto, watching from the sidelines, noticed something subtle—the twins had taken noticeably longer to finish that game. A smile crept onto his face as he murmured:
"So they haven't given up yet. Even against opponents this strong, they're still sticking to the data till the very end~"
Next was Yūho's serve again. The middle schoolers watching were already starting to squirm. This strength that transcended data countered Inui and Yanagi completely. To make Data Tennis work, you had to have the raw ability to match.
The high schoolers, on the other hand, looked pretty pleased. Finally, they had hope of winning a match. Of course, the first-string members didn't show much reaction. Especially Byoudouin—his expression stayed icy calm.
"Ace! 15-0!"
"Ace! 30-0!"
"Ace! 40-0!"
Three straight serves. Yūho's serve speed was still too much for Inui to react to. It was far beyond his Waterfall Serve, but his face showed no panic. His glasses hid his eyes, making it impossible to tell what he was thinking.
Just as Yūho tossed the ball, Inui suddenly let out a low shout and sprinted to the far left corner. With the sound of racket meeting ball, he stretched out just in time—barely managing to intercept it at the very tip of his racket.
Before the middle schoolers could even cheer, Inui Sadaharu's racket was blasted out of his hand by the force of the serve. Clearly, Yūho's serve wasn't just fast—it packed serious power too.
"Game! Japan team! 5-4!"
"He actually returned it?!" Yūho hadn't expected that either. Even though he won the point, he didn't look pleased.
"It's the data! They managed to collect our Fusion data in such a short time!" Yūma said with a serious tone.
"Let's finish this fast, aniki! We can't drag this out any longer!" Yūho responded with a tense expression.
The Mutsu brothers had already decided—they were going to go all out and end this quickly. But things didn't go the way they planned. With the data now updated, Inui and Yanagi Renji ignored their bodies' warning signs and exploded with everything they had.
Combined with their data analysis, they started clashing head-on with the Mutsu brothers. The scene on court turned strange. Inui and Yanagi were shouting constantly, pushing their bodies to chase every ball with everything they had.
Meanwhile, the Synchronization aura between the Mutsu brothers kept shifting back and forth between them. Neither side backed down. It was clearly a final showdown, and the score kept rising on both ends.
"Game! Second-string selection! 5-5!"
Thanks to their burst of effort, Inui and Yanagi finally took a game back. But judging from the sweat pouring down their foreheads, they were clearly not in great shape. They weren't just physically straining themselves—they were pushing their brains into overdrive for high-speed calculations.
Next was Yūma's service game. Yanagi anticipated early with his calculations, but even so, he couldn't return every serve. One misread later, and they failed to break.
"Game! Japan team! 6-5!"
With Yūma holding serve, Inui and Yanagi were still teetering on the edge. They absolutely couldn't lose the next game, or the match would be over.
As Inui walked to the baseline, he felt an overwhelming pressure descend on him. He knew it was a mental effect. Thankfully, he'd trained himself to handle pressure much better than before.
Steadying his mind, he stopped hesitating and launched his Waterfall Serve. Even though he knew it wouldn't work on Yūho anymore, he still gave it a shot. Sure enough, Yūho returned it with ease, and both sides entered into another heated rally.
"0-15!"
"15-15!"
"15-30!"
"15-40!"
"30-40!"
Just like the last game, the score kept swinging back and forth. Before they knew it, they were already at match point. But at this point, both pairs were visibly spent.
Inui and Yanagi didn't even need mentioning, but the Mutsu brothers were gasping for air too. Sweat had soaked their uniforms, and steam was even rising from their bodies. Clearly, Fusion was draining their stamina at an alarming rate.
Inui served another Waterfall, but its speed had dropped to 218 kilometers per hour. Still fast, but anyone could tell—he didn't have much left in the tank.
Despite both sides being exhausted, they threw themselves into another fierce rally. After five or six intense exchanges, the Synchronization between the Mutsu brothers suddenly vanished. This unexpected shift caught Inui and Yanagi off guard.
"Crosscourt shot probability is… what?! The data's off—no, the opponents suddenly weakened!" Yanagi had been in the middle of calculating the trajectory when he sensed something wrong. But it was already too late. Yūma took the opportunity and slammed the ball between Yanagi's feet.
Inui, standing behind Yanagi, realized what was happening and rushed forward to cover—but his foot suddenly gave out. He stumbled forward a few steps, and that brief delay let the ball bounce out of bounds.
"Game! 7-5! Match over! Total score 2-1! Winner: Japan team!"
"Didn't expect you senpai to cancel your Synchronization at the end. Looks like we lost this match," Yanagi said with a bitter smile as he walked up to the net.
"When playing against Data Tennis players, the most important thing is catching them off guard! That's what Mitsuya-san taught us!" Yūma replied with a grin.
"I see! You two have been acting like you were obsessed with Synchronization since the last set. And right at the key moment, you turned the tables on us!" Inui finally pieced it all together.
"Keep at it, kōhai! To push us this far in doubles—one day, you're both gonna become amazing doubles players!" Yūho stepped forward too, smiling as he reached out to shake hands with Inui and Yanagi.